1. Field of the Invention
This invention relates to a sheet-bundle stacking apparatus, and more particularly to an apparatus for stacking a plurality of bundles of sheets, each bundle being properly banded, in their horizontal postures so as to be subjected to the subsequent packing process.
2. Brief Description of the Related Art
As a typical packing method for papers of value such as, for example, bank notes, constant numbers of sheets (for example, one hundred sheets) are banded to form bundles of sheets, and constant numbers of such bundles of sheets (for example, ten bundles) are stacked in their horizontal posture to form blocks of bundles of sheets and again banded so that, in this way, the bank notes are packed in a serial ordinator. This packing method is likewise applicable to other papers of value such as security papers, post cards, lottery tickets and the like.
In a known apparatus for stacking bundles of sheets as discussed, for example, in Japanese Laid-open Patent Application No. Hei 5-178520, a group of bundles of sheets received in the arrangement of a row from the preceding process are carried at two opposite sides of their lower surfaces by a sheet-bundle pool table which comprises a pair of support plates, and this pool table is opened at opposite sides of the group of bundles of sheets so that the group of bundles of sheets are dropped onto a stacking table below the pool table. This procedure is repeatedly performed to stack the bundles of sheets in their horizontal posture on the stacking table. The bundles of sheets are pooled on the pool table and stacked on the stacking table while being restricted by pairs of opposing side ruler plates disposed along two opposite sides in the longitudinal direction of the pool table and stacking table. As the number of bundles of sheets stacked thereon is increased, the stacking table is lowered along the inner sides of the side ruler plates, thereby forming many blocks of constant numbers of bundles of sheets on the stacking table.
The blocks of the constant numbers of bundles of sheets stacked in their horizontal posture are transferred in a row along a path between the side ruler plates, by a pusher traveling along the path and gradually expelled, one block by one block, from an exit at a distal end of the path, first with the leading block. After completion of the expulsion of the last block, another procedure for stacking blocks of sheets onto the stacking table is resumed.
However, the conventional sheet-block stacking apparatus of the type mentioned has the shortcomings in that since many blocks of bundles of sheets stacked in their horizontal posture on the stacking table are expelled, one block by one block, from the exit which is located at the distal end of the path, it is necessary to stop the subsequent operation for stacking blocks of sheets during the time of expulsion of the previously stacked blocks and it is only after the completion of the expulsion of the last block that the subsequent stacking operation can be resumed. This is naturally inefficient in working performance and cannot meet the requirement of a highspeed stacking operation.
Further, since the pool table, which supports the bundles of sheets at two opposite sides thereof and drops them onto the stacking table therebelow, is of the construction openable at opposite sides thereof (i.e., two-sides open structure), it is not only complicated in structure but also inefficient in space, cost, etc. Sometimes, it becomes practically impossible to secure a space for forming a two-sides open structure depending on the line formation.
Also, in order to cope with a change in sheet size of the bundles, there is a need for the provision of a space adjusting mechanism for adjusting the spaces between the side ruler plates and between the two openings of the pool table, and this again makes the overall construction of the apparatus even more complicated.
Also, during the time the blocks of the bundles of sheets are transferred over a comparatively long distance and gradually expelled from one end of the stacking table by a pusher, the entire side surfaces of each block are contacted with and rubbed by the inner surfaces of the side ruler plates, and as a result, the bundles of sheets suffer from scratches.
The present invention has been accomplished in view of the above problems inherent in the prior art devices.